When double-balloon enteroscopy (DBE) debuted in 2001, it transformed endoscopic evaluation of the small intestine by allowing access to areas beyond the reach of conventional endoscopes.

Unlike conventional push enteroscopy, which stretches and lengthens the bowel as the endoscope advances, DBE uses a push-and-pull technique that effectively shortens the intestine. This is achieved by alternately inflating and deflating two balloons — one mounted on a plastic overtube fitted over the endoscope and the other on the scope's distal end — which pleat the intestine over the enteroscope as it progresses step-wise through the small bowel.

For the last decade, DBE has been successfully used to evaluate and manage gastrointestinal (GI) bleeding, abdominal pain, chronic diarrhea, tumors and other small bowel disorders. It is now also increasingly used to evaluate the intestine, stomach and bile duct in patients with surgically altered bowel anatomy such as gastric bypass, Billroth II gastrectomy and Roux-en-Y anastomosis during liver transplantation.

"We're seeing more and more referred patients who have altered bowel anatomy for multiple reasons," says Frank Lukens, M.D., of Mayo Clinic in Florida. "Some have GI bleeding or complications after gastric bypass. Others have bile duct stones and require endoscopic retrograde cholangiopancreatography (ERCP), which usually can't be performed in these patients using a standard ERCP endoscope. DBE-assisted ERCP (DBE-ERCP) is an option for people with altered bowel anatomy because of its ability to negotiate the sharp turns of the intestine."

He adds that despite the growing number of people with altered anatomy, DBE hasn't been well studied in this population. "The diagnostic yield of DBE in these patients seems to be similar to the diagnostic yield of all DBE, but studies have been small and there is little data regarding complications," he says.

To fill this knowledge gap, Dr. Lukens and colleagues looked at the diagnostic yield and complication rates in 62 patients with surgically altered bowel anatomy who underwent DBE at Mayo Clinic in Florida between 2006 and 2011:

Eleven of the procedures were DBE-ERCPs.

The majority of patients — 49 — had surgically altered anatomy as a result of bariatric surgery, nine had undergone nonbariatric Roux-en-Y reconstruction, and the remaining four had undergone either Whipple or Billroth II procedures.

Seventy-three percent of the DBE patients were women.

The mean age was 51 years.

The mean BMI was 28.2.

The most common indication for DBE was abdominal pain; acute cholangitis was the primary reason for DBE-ERCP.

Results

According to the review, the overall success rate for adequate examination of Roux limb was 92 percent, and the overall diagnostic yield of all DBE without ERCP was 61 percent, which is comparable to reports of diagnostic yield in patients with normal anatomy.

The diagnostic yield of targeted or random small bowel biopsy was relatively low — 9.4 percent — but it was 100 percent for small bowel aspirate for clinically suspected cases of bacterial overgrowth.

Dr. Lukens notes that the high success rate is an extremely positive finding.

"Adhesions and other bowel changes make DBE challenging in these patients," he says. "And often, patients have symptoms and we don't find anything to account for them. So the goal is usually to look at the anatomy and make sure there is nothing serious. And in the majority of patients, we accomplished that."

It was accomplished less often in patients undergoing DBE-ERCP. There, the success rate for adequate examination of the pancreatobiliary tree and therapeutic intervention was 64 percent. Other reports have noted a success rate for ERCP in normal-anatomy patients of more than 90 percent, compared with roughly 50 percent in those with altered bowel anatomy.

Dr. Lukens says even with DBE, it is difficult not only to reach the papilla of Vater but also to cannulate into the pancreatic or biliary duct. "The standard endoscope for ERCP is a side-viewing duodenoscope, but the double-balloon endoscope is front-viewing, which makes entering the bile duct and injecting contrast quite challenging," he says.

Other limitations include the smaller diameter of the DBE accessory channel, the length of the enteroscope and lack of ERCP accessories for this type of endoscope. "I basically have one catheter, one balloon and one cannula," Dr. Lukens notes. "With normal-anatomy ERCP, I have a lot of toys that make the procedure much easier, but here the options are limited."

Despite these results, Dr. Lukens favors DBE-ERCP for people with altered bowel anatomy. "With surgery — the only other option for these patients — morbidity goes up, and of course the procedure itself, hospital stay and recovery are so much more difficult, so it's worth giving DBE a try. The odds are better endoscopically than surgically, and the risk of pancreatitis is the same in both."

Conclusions

DBE in general comes with more inherent risk than conventional endoscopic procedures because of the deep intubation of the small bowel, limited flexibility and duration of the procedure. At Mayo Clinic in Florida, the average time of DBE without ERCP is 89.6 minutes and approximately 120 minutes with it.

In other studies, complication rates in normal-anatomy patients average around 1.5 percent, and increase to 3 percent in those with altered anatomy. The Mayo Clinic study did not find any serious complications, either early or delayed, in patients with altered anatomy undergoing DBE. Dr. Lukens says the disparity may be due to differences in patient populations, operator experience, anesthesia management and other variables, including length and complexity of afferent limbs and patient health.

In general, he says DBE has been shown to be a safe, feasible and effective procedure with a relatively high diagnostic yield. DBE, single-balloon enteroscopy, capsule endoscopy, spiral-assisted enteroscopy and other innovative endoscopic procedures are performed at all three Mayo Clinic sites.

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